A fragment of a human finger bone dating back up to 90,000 years has been found in the Saudi Arabian desert – and it could rewrite the history of mankind’s journey out of Africa.

The bone fragment, around an inch long, has been undiscovered for up to 90,000 years, in an area which was once a grassland teeming with wildlife.

Scientists previously believed that humans left Africa in a single migration 60,000 years ago – but the new find challenges that.

Researcher Michael Petraglia of the Max Planck Institute for the Science of Human History in Germany says, ‘This supports a model not of a single rapid dispersal out of Africa 60,000 years ago, but a much more complicated scenario of migration.

This handout image obtained from the University of Oxford/ Max Planck Institute shows fossil finger bones of Homo sapiens from Al Wusta, Saudi Arabia, a discovery that suggests modern humans had penetrated deep into Arabia already 85,000 years ago

‘This find, together with other finds in the last few years, suggests … Homo sapiens is moving out of Africa multiple times during many windows of opportunity during the last 100,000 years or so.’

Petraglia said that the find shows that people were crossing the interior of the land, not along the coast.

University of Oxford archaeologist Huw Groucutt said, ‘The big question now is what became of the ancestors of the population to which the Al Wusta human belonged.

‘We know that shortly after they lived, the rains failed and the area dried up. Did this population die out? Did it survive further south in Arabia, where even today there are mountainous areas with quite high rainfall and coastal regions which receive monsoonal rains?

‘Or did the drying environment mean that some of these people were ‘pushed’ further into Eurasia, as part of a worldwide colonisation?’